Touch.radiusX

Summary

Returns the X radius of the ellipse that most closely circumscribes the area of contact with the touch surface. The value is in CSS pixels of the same scale as Touch.screenX.

This value, in combination with Touch.radiusY and Touch.rotationAngle constructs an ellipse that approximates the size and shape of the area of contact between the user and the screen. This may be a relatively large ellipse representing the contact between a fingertip and the screen or a small area representing the tip of a stylus, for example.

Note: This attribute has not been formally standardized. It is specified in the Touch Events – Level 2Editor's Draft specification and not in Touch EventsRecommendation. This attribute is not widely implemented.

Syntax

var xRadius = touchItem.radiusX;

Return value

xRadius

The X radius of the ellipse that most closely circumscribes the area of contact with the touch surface.

The following simple code snippet, registers a single handler for the touchstart, touchmove and touchend events. When the src element is touched, the element's width and height will be calculate based on the touch point's radiusX and radiusY values and the element will then be rotated using the touch point's rotationAngle.